"From Up on Poppy Hill" is frankly stunning, as beautiful a hand-drawn animated feature as you are likely to see. It's a time-machine dream of a not-so-distant past, a sweet and honestly sentimental story that also represents a collaboration between the greatest of Japanese animators and his up-and-coming son.

"Poppy Hill" is directed by Goro Miyazaki, whose father, the Oscar-winning Hayao Miyazaki ("Spirited Away," "My Neighbor Totoro"), wrote the screenplay based on a graphic novel. The fantastical element present in the senior Miyazaki's films is not a factor here, but the father's ability to transport us to other worlds is very much echoed in the son's work.

That other world, the bustling Japanese city of Yokohama in 1963, may not sound like an enviable destination, but in the hands of Miyazaki and his team few places on Earth have looked as stunning as this hilly city whose port is filled with a gorgeous variety of ships and boats.

The year 1963 was not picked at random. It's the time all of Japan was gearing up for the 1964 Tokyo Olympics, a key transition period that was, in the director's words, "an interval between a war overflowing with blood and an opulent economic era overflowing with money." Many Japanese, he adds, feel nostalgia for this period, and "From Up on Poppy Hill" is unabashedly nostalgic.

It's not just the beauty of the physical look of the period, with everything from houses to cars re-created in meticulous yet somehow poetic detail, that evokes a longing for the past. Even in dubbed English, the respect and politeness with which all the characters, even the teenage protagonists, treat one another is a far cry from what can go on in this day and age.

High school junior Umi (voiced by Irish actress Sarah Bolger of TV's "The Tudors") is the latest in the line of resourceful young women that feature in many Hayao Miyazaki films. With her father lost at sea during the Korean War and her mother studying in America, Umi has to keep an eye on her two younger siblings while doing a lot of the cooking and cleaning in the boarding house run by her kindly but reserved old-school grandmother.

Despite all this, Umi somehow finds time to do one more thing. Each and every morning, she runs two signal flags up the pole facing the harbor outside her hillside home. Why she does this is one of the gentle mysteries of "Poppy Hill's" plot, to be revealed with unhurried deliberateness.

As it turns out, one of Umi's classmates has noticed the flags and written the following poetic question in the school newspaper: "Fair Girl, why do you send your thoughts to the sky?" While Umi tries to figure out who that classmate might be, she and everyone else is captivated by a jump a young man makes from the roof of an enormous but dilapidated old Meiji-era building called the Latin Quarter that the boys in the school use as a clubhouse.

That young man would be Shun (Anton Yelchin), who jumps into a pool to protest that the school wants to raze the Latin Quarter and put a spanking new building in its place. In fact, the importance of the past, the notion that you can't move into the future without knowing and respecting it, soon reveals itself as "Poppy Hill's" overriding theme.

The inside of the Latin Quarter, which we see when Umi, prodded by her younger sister, visits Shun at the school newspaper office, is "Poppy Hill" at its most fantastical. Decades of detritus clog every available space of a multi-story structure composed of nooks and crannies without end.

It will shock no one that Umi and Shun feel a strong, albeit demure, attraction to each other, but, surprising for a movie as genteel as this one, a very real-world obstacle is thrust in the path of their relationship.

And not just any obstacle but one rooted, no surprise, in the chaotic wartime past that the Miyazakis clearly feel should not be forgotten in the rush to be modern. "From Up on Poppy Hill" may be sweetness itself with a pop soundtrack including 1963's chart-topping hit "Sukiyaki," but that doesn't mean it doesn't have some serious stuff on its mind.